ITunes Song Won't Play On IPhone 4S?

Clarity by Zedd shows up with no artwork and won't play when i hit the play button. I need to re download this song on my phone like delete it and then download it.
How do I do this? Advice?

1. Plug in iPhone and go to iTunes on your computer
2. Go to Clarity and press delete on keyboard
3.Re-download song from wherever you got it from
4. Drag and drop into music folder on iPhone playlist.

If you downloaded it legally from iTunes do this… (Easy Method)
1. Go to Music app on iPhone
2. Go to song (Clarity)
3. Swipe on song and click delete
4. Go to iTunes
5. Go to More > Purchased > Music
6. Go to Zedd and Clarity will show
7. Click download icon

and there you go! Should work. If that doesn't work, then the file is corrupted because i don't know. Illegally download an m4a file and put it on your phone.